Adaptive replacement cache (ARC) is a data replacement algorithm for managing a cache region. In ARC, a cache region is divided into a region managed based on Recency and a region managed based on Frequency. In addition, the size of each region is optimized based on a history of data evicted from each region.
Hierarchical-ARC (H-ARC) is a technology based on ARC. In H-ARC, a cache region is further divided into a region for dirty data and a region for clean data.
The following technologies related to caches are also proposed. For example, a hybrid disk drive is proposed in which data blocks stored in a flash memory included by the disk drive are managed by ARC. In addition, a disk control device is proposed in which dirty data to be written back is compressed on a cache region to prepare for a write to a disk drive. Examples of the related art include Japanese Laid-open Patent Publication No. 2013-196755, Japanese Laid-open Patent Publication No. 07-129470, and “H-ARC: A Non-Volatile Memory Based Cache Policy for Solid State Drives.”